This invention relates to the art of surface scanning and imaging, and more particularly to a new and improved ultrasonic method and apparatus for surface scanning and imaging.
One area of use of the present invention is in fingerprint scanning and imaging, although the principles of the present invention can be variously applied to imaging surface topology using ultrasound. In optical techniques for fingerprint scanning, reflections from small air pockets under the fingerprint ridges reduce the image quality thereby requiring image processing techniques which are quite complex and costly to implement and which themselves can cause unwanted artifacts or possibly remove valid components of the image. Another problem with optical techniques is that once the ridge structure of a finger is worn smooth enough optical systems no longer are able to acquire good quality images.
It would, therefore, be highly desirable to provide a system and method for imaging surface topology which provides high quality images thereby reducing the complexity and cost of subsequent image processing and which, in the case of personal identification, has the capability of imaging structures which lie beneath the surface of the skin which can be used for identification.